diff --git a/cfg_checker/modules/network/mapper.py b/cfg_checker/modules/network/mapper.py
index cea81bf..482bdfa 100644
--- a/cfg_checker/modules/network/mapper.py
+++ b/cfg_checker/modules/network/mapper.py
@@ -252,16 +252,24 @@
                 # there is such interface in this level?
                 if interface not in tree[lvl]:
                     # - IF not present
-                    # -- get parents, add
-                    _p = res[interface]['lower']
+                    _n = ''
+                    if interface not in res:
+                        _n = 'unknown IF'
+                        _p = None
+                        _c = None
+                    else:
+                        # -- get parents, add
+                        _p = res[interface]['lower']
+                        # -- get childs, add
+                        _c = res[interface]['upper']
+
                     # if None, put empty list
                     _p = _p if _p else []
-                    # -- get childs, add
-                    _c = res[interface]['upper']
                     # if None, put empty list
                     _c = _c if _c else []
                     tree[lvl].update({
                         interface: {
+                            "note": _n,
                             "parents": _p,
                             "children": _c,
                             "size": len(_p) if len(_p) > len(_c) else len(_c)
@@ -278,12 +286,28 @@
                     return
 
             def _put(cNet, cIndex, _list):
-                for _cI in range(cIndex, len(_list)):
+                _added = False
+                _actual_index = -1
+                # Check list len
+                _len = len(_list)
+                if cIndex >= _len:
+                    # grow list to meet index
+                    _list = _list + [''] * (cIndex - _len + 1)
+                    _len = len(_list)
+
+                for _cI in range(cIndex, _len):
                     # add child per index
                     # if space is free
                     if not _list[_cI]:
                         _list[_cI] = cNet
+                        _added = True
+                        _actual_index = _cI
                         break
+                if not _added:
+                    # grow list by one entry
+                    _list = _list + [cNet]
+                    _actual_index = len(_list) - 1
+                return _actual_index, _list
 
             # build network hierachy
             nr = node_data['networks']
@@ -316,7 +340,11 @@
                         # put current interface if this is only one left
                         if not _tree[_lv][_net]['children']:
                             if _net not in matrix[x]:
-                                _put(_net, y, matrix[x])
+                                _, matrix[x] = _put(
+                                    _net,
+                                    y,
+                                    matrix[x]
+                                )
                             y += 1
                         else:
                             # get all nets with same child
@@ -330,16 +358,25 @@
                                         # there is such interface on this level
                                         # get index
                                         _nI = matrix[x].index(_a[idx])
-                                        _put(_c, _nI, matrix[x+1])
+                                        _, matrix[x+1] = _put(
+                                            _c,
+                                            _nI,
+                                            matrix[x+1]
+                                        )
                                     else:
                                         # there is no such interface
                                         # add it
-                                        for _nI in range(len(matrix[x])):
-                                            if not matrix[x][_nI]:
-                                                matrix[x][_nI] = _a[idx]
-                                                # also, put child
-                                                _put(_c, _nI, matrix[x+1])
-                                                break
+                                        _t, matrix[x] = _put(
+                                            _a[idx],
+                                            0,
+                                            matrix[x]
+                                        )
+                                        # also, put child
+                                        _, matrix[x+1] = _put(
+                                            _c,
+                                            _t,
+                                            matrix[x+1]
+                                        )
                                     # remove collected nets from processing
                                     if _a[idx] in nets:
                                         nets.remove(_a[idx])